Laryngotracheal Reconstruction 

Updated: Apr 08, 2016
Author: Brian Kip Reilly, MD; Chief Editor: Arlen D Meyers, MD, MBA 

Overview

Background

Subglottic stenosis (SGS) is a condition of the neonate's or infant's upper airway that is caused by either abnormally small development of the cricoid ring section (congenital) or through injury that is the direct or indirect result of trauma and inflammation (acquired). SGS dramatically increased in the mid-20th century following the development of neonatal ICUs (NICUs) and ventilator support of premature infants using endotracheal intubation for prolonged periods of support. Today, acquired SGS remains the most serious acquired airway abnormality in the pediatric population from prolonged intubation.[1]

Premature infants who developed significant SGS in the past most often required tracheotomy tube placement, followed by a prolonged period of weaning from elevated oxygen levels as their pulmonary status improved. See the image below.

Subglottic Stenosis in patient requiring tracheost Subglottic Stenosis in patient requiring tracheostomy

For many decades, SGS was not able to be corrected by a surgical procedure. Now, through laryngotracheal reconstruction, surgeons can enlarge the narrowed segment of the infant's trachea and achieve successful removal of the tracheotomy tube. This surgical advancement was finally attained by the collective work of numerous surgeons who developed open surgical repair of the injured cricoid and tracheal rings. This procedure has been named laryngotracheal reconstruction (LTR) or laryngotracheoplasty.

LTR was developed in the 1960s and 1970s by numerous prominent surgeons working in Europe, Canada and the United States. Among the most prominent were Drs. Bertel Grahne, John Evans, George Buchanan Todd, Blaire Fearon, and Robin Cotton.[2] They designed LTR as an operation that increases the airway lumen by splitting the narrowed segment of cartilaginous rings and then suturing harvested cartilage grafts to increase the lumen’s diameter of the trachea. Successful LTR thereby creates a larger airway and improves and often alleviates the airway obstruction, allowing for the tracheotomy tube to be removed and the child to be decannulated.

Patients require LTR because of laryngeal or tracheal stenosis, complete atresia, or in rare cases severe tracheomalacia after tracheostomy. SGS, or severe narrowness of the airway, can be either congenital or acquired. Congenital stenosis occurs from failed recannulation of the airway during embryonic development. Acquired stenosis is the result of an inflammatory process or insult from the endotracheal tube.

Balloon dilation of the airway has been performed prior to open airway surgery. See the images below.

Membranous Subglottic Stenosis Membranous Subglottic Stenosis
Balloon Dilation for membranous subglottic stenosi Balloon Dilation for membranous subglottic stenosis
Post-dilation Subglottic Stenosis Post-dilation Subglottic Stenosis

Pathophysiology

Congenital SGS is considered to be congenital in absence of acquired causes of stenosis or a history of endotracheal intubation. Congenital SGS has 2 main types: membranous and, more commonly, cartilaginous. The membranous type is a soft-tissue thickening of the subglottis caused by hyperplastic mucous glands with no inflammatory reaction or increased fibrous connective tissue. The cartilaginous types are more varied in etiology but most commonly involve a thickening or deformity of the cricoid cartilage such as an overly elliptical cricoid cartilage.[3]

Acquired SGS is typically caused through injury that is the direct or indirect result of trauma and inflammation such as endotracheal intubation. The pathophysiology of acquired SGS secondary to prolonged endotracheal intubation is well described. Endotracheal tube intubation causes pressure necrosis and subsequent mucosal edema and ulceration at the point of contact with the tissue. As this edema and ulceration progresses, normal ciliary flow is interrupted, which leads to secondary infection and perichondritis. With further infection, cartilage necrosis occurs. This necrosis and ulceration heals by secondary intention and causes formation of granulation tissue and deposition of fibrous tissue in the submucosa, leading to narrowing of the endolarynx. Additionally, repeated intubations cause increased mechanical mucosal trauma and greater amounts of inflammatory response and scar tissue formation, leading to SGS.[3]

The tracheal narrowing can involve several segments of the airway, may be secondary to complete tracheal rings, and can be either firm or soft, circumferential or longitudinal, smooth or irregular, mature or immature. The Cotton-Myer grading system is used to measure the severity of subglottic or tracheal stenosis and is determined with endotracheal tubes demonstrating a leak.[4] The grading system is as follows:

  • Grade 1 – 0-50% obstruction

  • Grade 2 – 51-70% obstruction

  • Grade 3 – 71-99% obstruction

  • Grade 4 – No detectable lumen

Table 1. Severity of subglottics stenosis as determined by endotracheal tube size with leak at 10-25 cm of water. (Open Table in a new window)

 

Endotracheal Tube Size

2

2.5

3

3.5

4

5

5.5

6

6.5

Patient Age

 

 

 

 

 

 

 

 

 

 

Premature

No lumen

40%

30%

No stenosis

 

 

 

 

 

 

0-3 mo

No lumen

68%

48%

26%

No stenosis

 

 

 

 

 

3-9 mo

No lumen

75%

59%

41%

22%

No stenosis

 

 

 

 

9 mo to 2 y

No lumen

80%

67%

53%

38%

20%

No stenosis

 

 

 

2 y

No lumen

84%

74%

62%

50%

35%

19%

No stenosis

 

 

4 y

No lumen

86%

78%

68%

57%

45%

32%

17%

No stenosis

 

6 y

No lumen

89%

81%

73%

64%

54%

43%

30%

16%

 

 

Grade IV

Grade

III

Grade

III

Grade

III

Grade

II

Grade

II

Grade

I

Grade

I

Grade

I

 

 

Anatomy

The pediatric larynx is approximately one third the size of that of an adult, with the most narrowed portion being that formed by the elliptical or signet shaped cricoid cartilage ring.

The subglottis, from the lower surface of the true vocal cords to the inferior surface of the cricoid, is the narrowest aspect of the pediatric airway. The tracheal narrowing can involve several segments of the airway, may be secondary to complete tracheal rings, and can be firm or soft, circumferential or longitudinal, smooth or irregular, mature or immature.

The subglottis is defined as the area extending from the lower surface of the true vocal cords to the lower surface of the cricoid ring. The pediatric larynx is approximately one third the size of that of an adult, with the most narrowed portion being that formed by the signet shaped cricoid cartilage ring. The infant larynx is positioned higher in the neck than the adult larynx; the cricoid is positioned approximately at the fourth cervical vertebrae. In comparison, the adult cricoid rests at about the level of the sixth cervical vertebrae.

The normal subglottic lumen diameter in the full term neonate range from 4.5-5.5 mm and in premature babies is approximately 3.5mm. A subglottis of 4 mm or less in a full term neonate is considered narrow.

Indications

A child who is symptomatic from SGS requires surgical correction of the airway. LTR is the most reliable treatment for Cotton-Myer Grades II or III. The lower Grade I is treated with either dilation, or cricoid split surgery. Grade IV stenosis is more challenging and may require, tracheal resection, slide tracheoplasty, or permanent tracheostomy.

Balloon dilation of the airway has been performed prior to open airway surgery.[5] See the image below.

Balloon Dilation of Cartilagenous Stenosis Balloon Dilation of Cartilagenous Stenosis

In select patients, balloon dilation can be performed in lieu of LTR, or in severe cases of Grade III stenosis, in combination with LTR. Oftentimes, the dilation is performed after LTR during the initial healing process to further improve soft tissue swelling, edema, and granulation tissue from the incorporating graft.

Outcomes

The success of laryngotracheal reconstruction is generally defined by overall decannulation rates and voice quality. Excellent results have been reported for both single-stage and double-stage procedures. See the image below.

Fully healed graft at 6 months Fully healed graft at 6 months

Decannulation rates are typically higher for single-stage LTR but this is likely due to the increased disease severity in patients who undergo double-stage reconstruction.

 

Periprocedural Care

Pre-Procedure Planning

All infants and children with SGS have complex medical histories and require careful and thorough evaluations to assess their candidacy for LTR. Preoperative consultations are made with the pediatrician and a cohort of pediatric medical specialists. Children with significant medical histories may benefit from seeking consultation with a gastroenterologist, pulmonologist, cardiologist, neurologist, or anesthesiologist to optimize the patient.

Gastroesophageal reflux (GERD) must be appropriately evaluated and medically controlled; daytime and nighttime oxygen must be assessed and weaned prior to any surgical intervention; an appropriate anesthetic plan must be in place for the procedure; neurological status must be adequate for respiratory drive; underlying seizure disorders needs to be controlled; and the patient must not need ventilator assistance or positive pressure assistance.

A thorough history should be performed addressing birth history and in particular prematurity, number of intubations, feeding difficulties, presence of GERD, and other medical comorbidities. Children with SGS present with stridor, which can be inspiratory or biphasic in nature. Infants in the NICU may have repeatedly failed extubation trials and have no leak with appropriate sized endotracheal tubes. Recurrent episodes of croup before age 9 months also raise suspicion for significant SGS. These patients often have a history of respiratory infections that result in multiple hospitalizations or multiple failed extubation attempts.

A complete physical examination is performed, which includes a flexible laryngoscopic examination to assess the patency of the choanae, presence of laryngeal reflux, vocal fold mobility, and possible secondary airway lesions such as laryngomalacia or vallecular cysts.

Neck and chest radiography can be helpful if vascular ring, sling, or aberrant cardiopulmonary anatomy is a concern. If extrinsic compression is suspected, CT angiography/magnetic resonance angiography can be helpful as an adjunct to endoscopy. Barium esophagraphy is can be obtained in patients who have a history of tracheoesophageal atresia/fistula, aspiration, dysphagia, or neurological impairment.

Preoperative rigid endoscopic evaluation of the laryngotracheal stenosis and accurate functional evaluation of the supraglottis and glottis is crucial to a successful LTR outcome.[6] Rigid endoscopy is usually performed as a direct laryngoscopy and microlaryngoscopy with bronchoscopy in the operating room with the patient spontaneously ventilating. During this examination, a telescope is passed from the supraglottis down to the carina to accurately assess the entire airway. In cases of significant stenosis, a scope can sometimes not be passed. Photographic documentation and video recording are an essential part of this exam. See the image below.

Long segmented and Circumferential Tracheal Stenos Long segmented and Circumferential Tracheal Stenosis

The nature of the stenosis is accurately recorded including length, consistency, location, maturity, and the presence of any co-existing lesions. The airway is also formally sized with uncuffed endotracheal tubes. The endotracheal tube size with an air leak present at 10-25 cm of water corresponds to the size of the airway and as a universal guide to severity of stenosis. This sizing technique can be used to assign the stenosis a grade using the Myer-Cotton grading system.[3]

Once a complete and accurate assessment of the airway has been performed, the nature of the operative intervention is determined.

Monitoring & Follow-up

The postoperative care of patients following LTR is critical to the success of surgery. Patients undergoing LTR are kept in the ICU, sedated and intubated, to facilitate wound healing. Meticulous care is necessary to avoid unplanned extubation. These patients require sedation and analgesia with or without neuromuscular blockade to prevent excessive head and neck movement and possible injury to the reconstructed airway or formation of granulation tissue and edema. A postoperative chest radiograph is obtained to exclude any pneumothorax or pneumomediastinum. Prophylactic antibiotics and antireflux medications are used in the postoperative period and the wounds are examined daily.

Adverse effects narcotics can lead to prolonged weakness, withdrawal symptoms, and poor cough, which can predispose the patient to pneumonia.

After a single-stage LTR, the patient is reexamined in the operating with direct laryngoscopy and bronchoscopy after 7-10 days. The nasotracheal tube is downsized. Intravenous steroids are initiated and a trial of extubation is planned for the following day provided the reconstructed airway is healing well. If the patient tolerates extubation, she is kept in the hospital for an additional 7 days while overcoming the effects of prolonged sedation and withdrawal. Two weeks after the initial procedure, another direct laryngoscopy and bronchoscopy is performed to assess progress of the reconstructed airway. See the image below.

Anterior Graft Healing (2 weeks after LTR) Anterior Graft Healing (2 weeks after LTR)

Throughout the recovery process, endoscopic interventions may need to be performed to dilate the airway or remove granulation tissue.

In patients who undergo a double-stage LTR, the stent is typically removed 3-6 weeks after the initial procedure. At this time, the airway is examined after stent removal and endoscopic dilations can be performed, granulation tissue is removed, and graft healing is assessed. The patient is then brought back to the operating room a few weeks later for reevaluation with rigid bronchoscopy. If the airway size of the airway is adequate, the patient is admitted to the ICU for a 24-hour 48-hour capping trial. If the patient tolerates capping for 48 hours, the patient is then sent home capping for one month. After one month of capping, the patient is evaluated again in the operating room. If a well-healing airway is confirmed, the patient is admitted to the ICU for decannulation. Occasionally, prior to decannulation a sleep study may be performed with the tracheostomy tube capped.

 

Technique

Approach Considerations

The goal of any LTR is to increase the size of the airway, decannulate a patient who is tracheostomy tube dependent, and preserve laryngeal function (ie, voice). The key components are the division of the narrowed segment and subsequent placement of anterior and/or posterior cartilage interposition graft to widen the airway lumen.

The difference in single-stage versus double-stage LTR refers to the number of steps involved in the reconstruction. In a single-stage LTR, the tracheostomy tube is removed during the reconstruction with the use of an endotracheal tube as a stent before extubation. If the patient is to undergo a double-stage operation, then the tracheostomy is deliberately maintained, and a stent is placed, which is then removed after healing of the graft.

By definition, in a double-stage LTR, the tracheostomy tube is kept in place at the conclusion of the procedure. If the procedure is successful, the patient is decannulated during a separate hospital admission, usually several weeks or months later.[7] The advantage of single-stage LTR is immediate decannulation or avoidance of tracheostomy altogether. The double-stage operation involves the use of prolonged stenting (Montgomery, Albouker, Cotton Stent), while the single-stage LTR requires prolonged endotracheal intubation and sedation.

See the image below.

Stent suture placement Stent suture placement

Most recommend double-stage LTR when complex multilevel stenosis, higher grade stenosis, significant neurologic deficits or lung disease, or anatomy that makes reintubation technically difficult is noted.

Single-stage Laryngotracheal Reconstruction

A direct laryngoscopy and rigid bronchoscopy is repeated in all patients prior to performing open airway reconstruction. Once the appearance of the airway has been confirmed, the patient is intubated orotracheally in preparation for the LTR. The patient is carefully positioned supine with the neck extended. The incision is planned for a right-sided rib cartilage graft and a midline neck incision. These are injected with 1% lidocaine with 1:100,000 epinephrine. The skin is then prepped, and the patient is draped, keeping the donor site separate from the neck.

First, the rib cartilage graft is harvested. See the image below.

Chest and Neck incision Chest and Neck incision

A transverse incision is made through the skin into the subcutaneous tissue. The subcutaneous fat is then removed with electrocautery. The overlying musculature is then divided with electrocautery until the rib and its perichondrium are identified. Care is taken to preserve the perichondrium on the anterior surface of the rib. Incisions are made both superiorly and inferiorly with a No. 15 blade into the perichondrium of the rib near the bony cartilaginous junction. The underlying perichondrium is then elevated from the rib. A Doyen retractor is placed under the rib and superficial to the perichondrium. The rib is then divided at the bony cartilaginous junction.

Careful dissection is then performed to medially elevate the perichondrium from the undersurface of the rib to protect the underlying pleura. Once a 2-cm to 3-cm segment of cartilage is elevated, the cartilage graft is harvested. Hemostasis is achieved, and a leak test is performed. Any pleural defect identified should be immediately repaired. The wound is then closed in layers and a Penrose drain is left in place.

Attention is then turned to the neck, where a transverse skin incision is made in the midline through the subcutaneous fat and through the platysma. Subplatysmal flaps are then raised superiorly to the level of the hyoid and inferiorly to the sternal notch. The strap muscles are divided in the midline to expose the thyroid gland and the trachea. Additionally, the exposure is continued superiorly to the thyroid notch and the hyoid. The thyroid gland is divided in the midline to expose the entire airway from the thyroid notch to the approximately the sixth tracheal ring. Prolene retraction sutures are then placed through the cricoid cartilage on either side of the midline.

Either an RAE tube or armored endotracheal tube is prepared and a sterile circuit is placed onto the field to switch ventilation from an orotracheal tube from above to a distal endotracheal after the airway is opened. See the image below.

Armored Tube placed after removal of tracheostomy Armored Tube placed after removal of tracheostomy tube

Using a right-angle clamp and a Beaver blade, an anterior cricoid split is performed. The thyroid notch is used to maintain a midline incision. The extent of the incision depends on the site and extent of the airway pathology. Once the laryngofissure is performed, care is taken to assess the airway pathology and tailor the intervention. If posterior narrowing is seen, a posterior cricoid cartilage division may be performed. Prior to dividing the cartilage, it is injected with local with epinephrine (either 0.5% lidocaine with 1:200,000 or 1% lidocaine with 1:100,000 epinephrine). The No. 64 blade is then used to divide the posterior cricoid cartilage. A hemostat clamp is used to distract the cartilage to ensure that this division is complete.

Occasionally, the posterior division is extended superiorly into the interarytenoid region if posterior glottic stenosis is present.

The rib grafts are carved on a back table. The posterior graft is fashioned into a rectangle with a posterior flange. The width is approximately 5 mm with a 1 mm flange and the height is approximately 10 mm but this varies. The perichondrium is preserved on the luminal surface of the graft. After, the anterior cartilage graft is carved into a boat shape. See the image below.

Anterior Graft Placement Anterior Graft Placement

The length varies depending on the length of the anterior laryngofissure. See the image below.

Rib graft with preservation of perichondrium Rib graft with preservation of perichondrium

Again a flange is made and the ends are tapered to conform to the distracted airway.

Next, the posterior cartilage graft is placed by distracting the cricoid ring. The flange of the posterior cartilage graft and the natural recoil of the cricoid ring secure the graft into position. The airway is then examined from above with a telescope to confirm proper placement of the graft. Once this is done, the patient is then intubated nasotracheally with an appropriate sized nasotracheal tube. The end of nasotracheal tube is placed just distal to the anterior laryngofissure and the tube is secured.

Next, the anterior graft site is secured with 4-0 Prolene in a horizontal mattress suture technique. The sutures are placed submucosally on the intraluminal side of the trachea. The graft is then parachuted into position once all of the sutures have been placed. Saline is then instilled into the wound bed and a Valsalva is performed to check for an air leak. Ideally, the graft is placed in airtight fashion to minimize graft infection. The thyroid gland can be closed over the graft and the strap muscles are reapproximated in the midline. The wound is closed in layers over a Penrose dressing.

When a preexisting tracheostomy is in place, the surgeon must decide whether to perform a single-stage operation with decannulation or to keep the tracheostomy tube in place. In this operation, the patient’s stoma site is excised with the initial transverse skin incision. The airway is subsequently exposed in a similar fashion taking care to expose the airway distal to the tracheostoma. Then, the patient’s trachea is divided inferiorly to include the tracheostoma. A longer anterior cartilage graft is required to span the length of the anterior airway division. The anterior graft is then secured in a similar fashion and the patient’s incision is closed as above.

Double-stage Technique

The double-stage technique involves slight modifications from the single-stage technique described above since the patient has a tracheostomy in place. Initial decisions are directed towards addressing the tracheostoma. In double-stage LTR, the tracheostomy is preserved, and typically a suprastomal stent is placed into the airway to support the cartilage grafts. In most cases, the incision and dissection avoids violation of the stoma site. If exuberant granulation tissue is present either at the skin or tracking into the trachea, revision of the tracheostoma at the same operation may be performed.

In double-stage LTR, once the posterior cartilage graft is positioned, a stent is used in the airway to provide framework for mucosal healing. Stents give support, protect against graft displacement, and help prevent scar tissue from causing contracture. The selection of which stent to use is by surgeon preference. Aboulker and cylindrical silastic stents are two of the more commonly used stents. The stent is sized to sit from a level inferior to the arytenoids, between the vocal cords, to just above the tracheostomy. The stent is anchored with a non-absorbable suture through the strap muscles and cricoid. It is tied into approximately 2 cm of knots and allowed to exit the neck at one side of the transverse skin incision. The stent is removed by cutting this suture during a separate procedure approximately 3-6 weeks after it is placed. Some patients may require longer stenting times.

At the conclusion of the double-stage LTR, patients should have a secure airway because of the existence of an undisturbed tracheostomy. All of those involved in the care of these patients must understand that a stent is in place suprastomally. If the patient is accidentally decannulated during this time, intubating the patient through the mouth is impossible without removing the stent.

Cartilage Rib Graft

The mainstay graft material is cartilage from either the rib or the thyroid. Some surgeons prefer use of ear or thyroid cartilage because of less donor site morbidity.

The following surgical steps are performed for the rib cartilage removal:

  1. The right fifth rib is selected. An incision is made in the inframammary incision. In females, an estimated future breast crease is selected for women.

  2. Dissection is carried down onto the rib with Bovie cautery, carefully splitting the intercostals.

  3. The overlying periosteum is protected from thermal damage from Bovie cautery.

  4. A straight appearing nonbony portion of cartilaginous rib is then isolated.

  5. The undersurface of the rib is carefully dissected with a blunt instrument.

  6. The surgeon must harvest the desired length of rib base upon the length of the stenosis that needs to be repaired and whether anterior and posterior grafts must be placed.

  7. A pneumothorax must be avoided, and the surgeon must ensure that no defect is present in the pleura by irrigating the wound with saline. If a leak is present, the pleural defect is sutured. A leak is reassessed by applying positive pressure ventilation.

  8. A Penrose dressing is then placed.

  9. The intercostal muscles are reapproximated with suture.

  10. The skin is sutured closed.